Difference Between Fork/Join Framework and ExecutorService in Java

// Java program to demonstrate the working of Fork/Join
// Framework

// Importing required libraries
import java.io.*;
import java.util.concurrent.ForkJoinPool;
import java.util.concurrent.RecursiveTask;

// Class 1
// helper class
class SearchTask extends RecursiveTask<Integer> {

    // Global variables
    int array[];
    int start, end;
    int searchElement;

    // Constructor for initialising globals
    public SearchTask(int array[], int start, int end,
                      int searchElement)
    {

        // This keyword refers to current object itself
        this.array = array;
        this.start = start;
        this.end = end;
        this.searchElement = searchElement;
    }

    // Method
    // @Override
    protected Integer compute()
    {

        // Returns the count computed by processSearch
        return processSearch();
    }

    // Method
    // To count the count of searched element
    private Integer processSearch()
    {

        // Initially count is set to zero
        int count = 0;

        // iterating using for loop
        for (int i = start; i <= end; i++) {

            // if element is present in array
            if (array[i] == searchElement) {

                // Increment the count
                count++;
            }
        }

        // Returning the count of searched element
        return count;
    }
}

// Class 2
//  Main class
public class GFG {

    // main driver method
    public static void main(String args[])
    {

        // Custom input array elements
        int array[] = { 1, 2, 6, 3,  4,  5,  6,
                        7, 8, 9, 10, 11, 12, 6 };

        // Custom element to be searched in array
        int searchElement = 6;

        // initializing starting and ending indices
        int start = 0;
        int end = array.length - 1;

        // Creating object of ForkJoinPool class
        ForkJoinPool pool = ForkJoinPool.commonPool();

        // Now creating object of above class
        SearchTask task = new SearchTask(array, start, end,
                                         searchElement);
        int result = pool.invoke(task);

        // Print and display the searched element
        // If found do display out the number of times it is
        // found
        System.out.println(searchElement + " found "
                           + result + " times ");
    }
}

// Java program to demonstrate the working of
// ExecutorService

// Importing required libraries
import java.io.*;
import java.util.Date;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

// Class 1
// helper class extending Runnable interface
class Service implements Runnable {

    // member variable of this class
    int i;

    // Constructor of this class
    public Service(int i)
    {

        // Initializing the counter variable
        this.i = i;
    }

    // Method
    // @Override
    public void run()
    {

        // Printing the counter
        System.out.println(i + " ");

        // Try block to check for exceptions
        try {

            // Making thread to sleep for 1 second
            // using the sleep() method
            Thread.sleep(1000);
        }

        // Catch block to handle the exceptions
        catch (InterruptedException e) {

            // Print the line number and the corresponding
            // exception occurred
            e.printStackTrace();
        }
    }
}

// Class 2
// Main class
// ExecutorUtility
public class GFG {

    // Main driver method
    public static void main(String[] args)
    {

        // Creating an object of ExecutorService class to
        // create fixed size thread pool
        ExecutorService es
            = Executors.newFixedThreadPool(5);

        // Print the time difference before completion
        System.out.println(new Date());

        for (int i = 0; i < 25; i++) {

            // Executes the given command at some time in
            // the future
            es.execute(new Service(i));
        }

        // Executor is shut down so that
        // its task can be considered complete
        es.shutdown();

        // Print the time difference after completion
        System.out.println(new Date());
    }
}